1. Field of the Invention
The present invention relates to a scroll type fluid transferring machine for sucking, compressing and discharging a fluid. More particularly, it relates to a total system rotation type scroll machine in which two scrolls are mutually combined and respectively rotated.
2. Discussion of Background
The principle of a scroll type fluid transferring machine, especially a scroll compressor has been known. The scroll compressor is a kind of a positive displacement type compressor in which a pair of scrolls are combined with each other to effect compression of a fluid.
In the ordinary scroll compressor, one of the scrolls is made stationary and the other is subject to an orbital movement with respect to the stationary scroll to effect the compression.
The principle of a total system rotation type scroll compressor in which both scrolls are respectively rotated around their own axial center, is also well known (in a publication such as Japanese Unexamined Patent Publication No. 46081/1980).
FIGS. 5a, 5b, 5c and 5d show the principle of the total system rotation type scroll compressor. A first scroll 1 is caused to rotate around its own axial center O.sub.1 by a driving source such as a motor, an engine, a turbine and so on. A second scroll 2 is also caused to rotate around its axial center O.sub.2 in synchronism with the rotation of the first scroll 1. A compression chamber 3, which is formed by combining the first and second scrolls 1, 2, moves toward the rotation centers as the both scrolls rotate while the volume of the chamber 3 is gradually reduced. The pressure of a gas confined in the compression chamber 3 increases and a highly pressurized gas is discharged through a discharge port 4.
FIG. 5a shows a state of the combined scrolls 1, 2 at its moving phase of 0.degree., in which the gas is sucked in the compression chamber 3. As the scrolls rotate as shown in FIGS. 5b to 5d, they assume the moving phases of 90.degree., 180.degree., 270.degree. and 360.degree. C. (0.degree.) succesively, whereby the compression chamber 3 gradually shifts toward their revolution centers with the result of reduction in the volume of the gas. The two scrolls 1, 2 provide sealing portions S by mutual contact of the side surfaces of the wrap plates 1a, 2a of the scrolls 1, 2. The sealing portions S are in alignment with each other in the radial direction of the first and second scrolls 1, 2; namely, they always take a constant positional relation in a static state of the scrolls.
However, in the conventional total system rotation type scroll compressor in which the second scroll is caused to rotate by the rotation of the first scroll through the mutual contact of the wrap plates without using an Oldham coupling, there are problems of generation of noises and friction caused by the mutual contact of the wrap plates because the second wrap plate 2a of the second scroll 2 is directly in contact with and driven by the first wrap plate 1a of the first scroll 1.